1. Field of the Invention
The present invention is related to a cap opening system and a method for opening a cap, and in particular is related to a system and method for removing a cap provided in the upper portion of a container body of a container.
2. Description of the Prior Art
A cap opening apparatus used in a sample preprocessing system or the like is an apparatus which automatically removes a cap provided in a container such as a test tube or the like. Various cap opening apparatuses have been proposed in the prior art, but any apparatus that can be applied to various types of containers and caps has not yet been put to practical use. Namely, there are a wide variety of container body shapes (lengths in particular) and cap sizes (thicknesses in particular) depending on the type of container. Accordingly, when the operation conditions of the apparatus are fixed or standardized, it is difficult to carry out a cap opening operation for containers having various container bodies and caps. Further, there are push-in caps and screw caps and the like. In the case of a push-in cap, it is preferred that the cap is rotated during the cap opening operation, while in the case of a screw cap, the cap must be rotated for opening it
As described above, the prior art cap opening apparatuses can merely raise and lower a container with a cap by a predetermined distance, and operate a holding mechanism or cap grasping mechanism for caps of containers having a predetermined diameter.
Recently, containers having various container bodies and caps are put to practical use, and for this reason there is a demand for a cap opening apparatus which has a relatively simple structure and can automatically adapt its operating conditions to the shape of the container body and the cap of a container even when various containers having different container bodies and caps are supplied to the apparatus.
Further, when one mechanism is provided to grasp the cap and a separate mechanism is provided to rotate the grasped cap, the structure of the apparatus necessarily becomes large and complex. Further, in this case, it is necessary to provide a separate driving source. Furthermore, in the case where caps having various diameters are to be handled, it is desirous that a predetermined grasping force is applied irrespective of the cap diameter and that the cap is rotated at high speed from the point in time when such predetermined grasping force is created, but mechanisms in response to such demand have not yet been realized up to now. The same demand also exists for other apparatuses that need to grasp and rotate objects.